Weft straightener



P 1966 e. A. BURKLUND 3,247,566

WEFT STRAIGHTENER 3 Sheets-Sheet 1 Filed NOV. 6, 1963 POWER POWER POWER POWER (POWER POWER MODU LE MODULE MODULE MODULE 1MODULE MODUYLEjj F SUPPLY W32 23 m -24' zs' if 26' 27 VOLTAGE INVEN O GLENN A. BURKLUIIIS ATTORNEYS April 6, 1966 a. A. BURKLUND 3,247,566

WEFT STRAIGHTENER Filed NOV. 6, 1963 3 Sheets-Sheet 2 INVENTOR GLENN A. BURKLUND ATTORNEYS April 26, 1966 s. A. BURKLUND WEFT STRAIGHTENER 3 Sheets-Sheet 3 Filed NOV. 6, 1963 60 CYCLES Fig.6

D WW E L MK R U B A N N E L G ATTORNEYS United States Patent 3,247,566 WEFT STRAIGHTENER Glenn A. Bnrklnnd, Fairfax, Va., assignor to Burklund Laboratories inc a corporation of Virginia Filed Nov. 6, 1963, Ser. No. 321,747 9 Claims. (Cl. 26-51..5)

This invention relates to improvements in weft straightening apparatus. More particularly, it provides an improved apparatus for correcting nonlinear conditions of the weft, or other transverse element, of a traveling woven web or sheet.

It is a principal object of the invention to provide improved appar-atus of -a type which is versatile to such an extent as to be able to correct the weft not only for simple skewing to one side, but also for complex distortions such as bows or ripples.

In the processing and handling of woven sheet materials, the transverse weft elements frequently become distorted out of right-angularity with respect to the longitudinal warp elements due to vigorous processing involved in rendering desired characteristics into the final material. Any particular zone of the transverse weft elements of the web of material may lead or lag with respect to the perpendicuiar average position thereof between opposite selvages of the sheet or web. This distortion, from the desired position of the weft elements may assume the characteristics of a diagonal line from selvage to selvage, or it may assume a bowed or waving characteristic wherein a particular typical weft element assumes the form of an arc, which a line from selvage to selvage would intercept as a chord when drawn perpendicular to the parallel selvages of the web or sheet. A multiplicity of such complex distortions appear similar to irregular sinusoidal variations, perhaps having slopes which reverse several times from selv-age to selvage. A further condition can exist wherein most of the length of each weft element is perpendicular to both selvages, but where minor lengths of the elements, assume a sudden and sharp variation from the perpendicular near one of the selvages. This distortion is frequently described by those skilled in the manufacture of woven sheet or web materials as a hook.

To the best of my knowledge existing mechanisms presently in use are unable to eificiently correct for the multiplicity of variations, which may be either of a leading or a lagging nature, and are unable to make the necessary mechanical corrections for hooked, bowed or wavy conditions without undue interaction with and consequent distortion of relatively straight remainders of the weft elements between the selvages. Many of the prior skew and bow correction mechanisms employ a tiltable roll or rolls, whose tilt increases or decreases tension on a web selvage to decrease the skew across the web, and often employ a bowed roll whose purpose is to variably tension the web at its center and thus tend to remove the bowed effect in the weft. In addition to the above approaches, others have been disclosed wherein a lateral roll is employed on a fixed axle, which roll is divided into adjacent sections capable both of idling and/or being positively and selectively driven for introducing mechanical straightening forces upon a web passing over each independent section by advancing or retarding the web on that particular section. In one particular embodiment apparatus has been disclosed. wherein a longitudinally sectioned roll is provided with a system of ratchets and pawls for accelerating portions of a web passing over the roll, and additional-powered rollers are placed in engagement with the sections of the divided roll so that each roll can impart a tensioning efiect on the web passing between the divided roll and the powered rollers. Such a; ratchet system tends to apply tension- "ice ing forces upon the web in an intermittent pulsating fashion since the advance of the tensioning force is achieved by intermittent engagement of the driven rolls with a shaft rotating with constant angular velocity, and such a system permits only advancing of certain roll sections, but never retarding of a section which is already too advanced.

A major object of my invention is to provide a composite correction roll subdivided into side-by-side independent sections of a number which will be determined by the degree of resolution required to render weft elements perpendicular to the selvages and dispose the wefts in a straight line between selvages, and these sections all being permanently positioned and rot-at-ably journaled on a longitudinal shaft extending beyond each end of the composite roll, each section having its own source of torque located therewithin and capable of applying a torque to the section to either advance or retard the section with respect to the average position of the composite roll.

Another important object is to provide as a separate source of mechanical torque within each section of thecorrection roll, an electric motor which derives its excitation through electrical conductors controlled by a separate electrical control circuit for each associated correction roll section. The power source used in the working embodiment of this invention takes the form of a permanent-rnagnet direct-current motor known as a torque motor having a cylindrical shape easily fitting inside a roll section. These motors are available on the commercial market as Pancake Torque Motors.

A further object is to provide control circuitry with sufficient electrical capacity to smoothly drive each correction-roll section independently of the others, while accurately proportioning the amounts of torque delivered to each section of the composite roll, and at the same time controlling excitation polarity to determine the direc tion of the torque. By this means I am able to provide. very smooth and continuous advancin or retardingtorques to the various roll sections to impart a pattern of resultant tensions of complex distribution with respect to the web. Manual controls placed in novel mutual relationship as described below assist an operator of the. weft straightener to correct the linearity of the weft as the web passes quickly through the apparatus.

Other objects and advantages of the invention will become apparent during the following discussion of the drawings, wherein:

FIG. 1 shows diagrammatically a layout of the present system, including a sectional correction roll and associated control circuitry;

FIG. 2 shows a detail of a typical section of the correction roll;

FIG. 3 shows a schematic diagram of the control circuit for one section of the roll;

FIG. 4 shows a detail view of one manual control mechanism;

FIG. 5 shows a perspective View of a manual control panel; and

FIG. 6 shows a modification of a portion of the circuitry of FIG. 3 to permit conversion of the system to render it adaptable to automatic control by photoelectric cell means.

In FIG. 1 a web 1 of woven material is shown passing under two idler rollers 2 and 9 and over a correction roll which is a composite roll formed by roll sections 3, 5, 6, '7', and 8, each of which contains its own torque mechanism as shown and described in connection with FIG. 1. Ordinarily, a weft straightener of the present type is used between two other material handling machines (not shown), such as a dying machine and a drier, which respectively feed the material v) to the weft straightener and draw the straightened material through and away from it, although the present machine can itself advance the material by its own torque capabilities.

The idlers 2 and 9 are also divided into sections which are freely journaled on fixed shafts 10 and 11. These shafts are supported in machine side-frames 12 and 13 and are held in place by any suitable means (not shown) which may also be made adjustable so as to permit changing of the relative positions of the rolls to accommodate various different sheet materials. The torque mechanisms within the correction roll sections 3, 4, 5, 6, 7, and 8 are mounted on and supported by a hollow shaft 14 which is also rigidly supported by machine side-frames 12 and 13.

Independent sources of electrical power are provided to operate the torque drives in the sections 3, 4, 5, 6, 7, and 8, and are respectively labeled power modules 15, 16, 17, 18, 19, and 29.

The modules each contain a circuit of the type shown in FIG. 3 and can be manually controlled by means shown in FIGS. 4 and 5 to supply power to a cable 21 entering the tubular shaft 14 which connects each power module to a corresponding torque motor within a roll section. Each torque motor applies to its roll section a torque proportional to the electric power supplied to it and in a direction determined by the electric polarity.

Each power module is controlled by a ganged pair of potentiometers 22, 22; 23, 23'; 24, 24; 25, 25; 26, 26'; and 27, 27' in the embodiment illustrated, although the invention is not limited to the use of potentiometers. These pairs of potentiometers each controls the polarity and magnitude of the electrical energy furnished by a power module to the torque mechanism within its corresponding correction roll segment, as described below.

All of the pairs of potentiometers are located adjacent to each other below a panel P, FIG. 5, conveniently positioned for an operator making manual adjustments. Referring to a typical control pair, the ganged potentiometers Z7 and 27', FIG. 4, are attached to a small spur gear 81 meshed with a quadrant gear 82 supported on a control lever 27" pivoted to a frame (not shown) below the panel P. The position of the lever 27" controls the polarity and amplitude of the electrical output from power module 20, such that zero torque is produced by the torque mechanism Within section 8 when the arm 27" is centered. Positioning the lever 27" to move the ganged potentiometers 27, 27' to one end of their respective resistance elements will cause full electrical output of one polarity to be received by the torque mechanism within the section 3 from power module 20 through cable 21, and cause full torque, for instance, in a clockwise direction. Moving the lever 27" to the other extreme will cause full reverse torque.

When forward torque is applied to roll section 8, the web selvage 28 being frictionally engaged with the surface, will be advanced relative to the remaining width of the web. However, when ganged potentiometers 27, 27' are moved to the opposite end of their respective resistance elements a reversal of polarity will cause corresponding retarding torque to be exerted to retard the web near the selvage 28. The details of the power modules are shown schematically in FIG. 3, and will be described in detail subsequently.

The purpose of the sectioned idler rollers 2 and 9 is to confine the web to as great a circumference of the torque-controlled correction roll as possible and thus increase the friction between the surfaces of the segments and the web to which longitudinal forces are being imparted. After the material leaves the rollers 9 any small kinks, due to the limited number of sections into which the power-driven roller is divided, tend to straighten out as a result of the tension maintained in the departing material.

FIG. 2 shows in detail the cross-section of a typical torque mechanism of the correction roll, which corresponds to section 8 in FIG. 1. This section includes the stationary hollow supporting shaft 14 about which a roll section cylinder 30 is disposed and journaled on suitable ball bearings 31 and 31'. The ball bearings 31 and 31' are press fitted on the supporting shaft 14, and the outer peripheries of the ball bearings support the inner periphery of the cylinder on spacer rings 33 and 33. The cylinder 30 is preferably rubber coated as at 49.

The cylinder drive comprises a pancake torque motor, a commercially available item consisting of a wound stator assembly 34 and an annular permanent-magnet rotor positioned between bearings 31 and 31. The rotor assembly is retained in the cylinder 30 by a ring 36 suitably secured therewithin. The cylinder also supports slip rings 37 and 38 which are electrically insulated from the metallic cylinder 3t) and from each other by an insulating ring 39. These slip rings are wired directly to brushes 40 and 41 which rotate with the cylinder 30 and ride on commutators 42 to deliver power to the stator winding 34 from the slip rings. This power, enters the motor in wires and 46 Within shaft 14 and is coupled to the rotating slip rings 37 and 38 through sliding contacts 43 and 53, respectively. A block of insulating material 44 supports and electrically isolates the slip ring contacts 43 and 53 from each other and from the shaft 14. Insulated conductors 45 and 46 enter into and form a part of the cable 21 shown in FIG. 1 and couple the power modules to the various torque motors.

The surface of each revolving cylinder 3t) of the composite correction roll, instead of being coated with rubber, can be otherwise treated, for instance by knurling, abrasive impregnation, or whatever common means is available to increase the coefficient of friction and prevent slippage of the web under conditions of maximum torque imparted to the web material by the surface 49 of the roll.

FIG. 3 illustrates schematically a typical power module, for instance the module 20, which may include the circuit values tabulated at the end of this specification to illustrate a working embodiment. The listed components are typical for operation of a torque motor capable of exerting 11 foot-pounds of torque. The object of the circuit shown in FIG. 3 is to deliver either no voltage at all at its output terminals T1 and T2 when the ganged potentiometers 27 and 27 are both centered, or to deliver a DC. voltage whose polarity depends on which side of center the ganged potentiometers are moved toward and Whose magnitude depends on how far the potentiometers are moved away from centered position. This circuit employs two similar but oppositely poled control and rectifier sub-circuits, one including respectively rectifiers 50 and 57 together with a bridge circuit composed of diodes 58, 59, 60 and 61, and the other including controlled rectifiers 62 and 69 with a full wave bridge 76, 71, 72 and 73. Each sub-circuit comprises a complete power supply capable of driving a permanent-magnet torque motor from an alternating current source 77, in a direction depending on polarity, and with a torque depending on the displacement of the potentiometers 27 and 27' from their centered positions.

The full-wave rectifier bridges of the two sub-circuits are connected in parallel with motor M but with their output polarities reversed. Only one sub-circuit can de liver an output at any time because the circuit parameters are selected such that the sub-circuit is non-conductive during at least one half the travel of the associated control potentiometer. All items in these sub-circuits are commercially available components.

An analysis of the operation of the upper of the two typical sub-circuits of FIG. 3 is based upon the operation of the silicon controlled rectifiers 50, 57 by the control of which a continuously variable root-mean-square value of an alternating voltage can be obtained. Silicon controlled rectifiers are solid state thyratron-like devices in which a gate signal on a control element initiates the conduction cycle of the rectifier after which the gate signal loses control until the A.C. voltage passes through zero and ends conduction of the rectifier for a complete half cycle during which the gate signal regains control. Rectifier 50 functions on the positive half cycle, and rectifier 57 functions on the negative half cycle of the A.C. source, and their. outputs are combined by electrical connection of the cathode of rectifier 50 to the anode of rectifier 57.

Rectifier 50 is controlled by a gate signal derived through diode 51, potentiometer 27, capacitor 56, and applied to the control element of the rectifier 50 through resistor 75. Diode 51 conducts on the positive half cycle of the sine wave which is impressed both on the anode of rectifier 50 and on the cathode of rectifier 57, and charges capacitor 56 through the variable control resistance 27. By virtue of the fact that capacitor 56 and resistance 27 comprise an integrating network, the voltage appearing across capacitor 56 lags the voltage impressed across the controlled rectifiers 50 and 57, tending toward 90 under optimum conditions. Thus, theoretically, it would seem possible to control the conduction angle of rectifier 50 over only 90 of its cycle. However, since the sine wave energy exciting the anode of rectifier 50 is derived from the same source to which diode 51 is connected, the seem ing 90 phase shift across capacitor 56 is not controlling because the capacitor retains a D.C. charge from cycle to cycle, which serves to forward bias the gate control member 50a. Thus, as resistance 27 is decreased the D.C. charge is increased on 56, and provides sufiicient residual charge on capacitor 56 to permit conduction of rectifier 50 over nearly 180 of the cycle when resistance 27 is reduced to zero ohms. Resistor 75 serves to limit the control electrode 50a current to prevent damage to the device when conducting over the full half cycle. Rectifier 57 together with capacitor 52, resistor 54, variable resistor 27, and diode 55 operates exactly as described above except that this operation occurs during the negative half cycle of the A.C. sine wave.

These components in combination control the output of an alternating current from nearly zero volts R.M.S. to full value of the R.M.S. voltage supplied by source 77. This variable output A.C. voltage is then supplied across the full wave bridge consisting of diodes 58, 59, 60, and 61 which converts it to D.C. which is then connected across terminals T1 and T2 leading to a torque motor M in series with a D.C. ammeter 74 serving as a visual indication of the torque of the motor and the direction in which it is applied. Controlled rectifier 62 together with diode 63, resistor 76, capacitor 68 and variable resistance 27', function exactly as rectifier 50 together with components '51, 75, 56, and 27 respectively; and controlled rectifier 69 together with diode 67, resistor 66, capacitor 64 and variable resistance 27' function exactly as controlled rectifier 57 together with components 55, 54, 52, and 27, respectively.

The polarity and magnitude of the D.C. voltage impressed across torque motor M is determined by the setting of ganged potentiometers of which variable resistances 27 and 27' are typical. By actual tests of a circuit having the values set forth in the table below, I have determined that when resistances 27 and 27 are both set at 3000 ohms, rectifiers 50, 57 and 62, 69 are not conductive, and the meter 74 reads zero in the center of its scale. eferring to FIG. 3, I have connected the arm of potentiometer 27 to the junction with diode 51, and on potentiometer 27' the arm is tied to diode 67. Thus, when the shaft 29 of the dual element control is set to its rotational mid-position, each resistance 27 and 27 totals 3000 ohms and zero voltage is delivered to motor M. The control lever 27 shown in FIGS. 4 and 5 is at this time in its centermost position. When the control lever 27" is moved so that the potentiometers are rotated fully clockwise, the resistance 27 is zero causing full voltage across motor M of such polarity as to create, for instance, a clockwise maximum torque accompanied by a maximum clockwise reading on the meter 74. The resistance 27 is now set at 6000 ohms and rectifiers 62, 69, are non-conductive. Conversely, shifting the control lever 27" so as to rotate the control fully counter-clockwise causes resistance 27 to'become 6000 ohms rendering rectifiers 50 and 57 non-conductive while causing resistance 27' to become zero thereby rendering rectifiers 62, 69 fully conductive, thus causing the motor to exert maximum counterclockwise torque, accompanied by a maximum counter-clockwise reading on the meter 74. Intermediate lever positions provide lesser values of voltage and motor torque.

FIG. 6 illustrates a modification of the power module, shown schematically in FIG. 3, wherein photoconductive cells and 81 in FIG. 4 can be substituted for variable resistances 27 and 27' in FIG. 3. This modificationwould permit, as shown in FIG. 6, an external voltage entering pairs of terminals 82 or 83 to light small lamps 78 and 79 of incandescent or neon type to illuminate, in degrees varying with brightness of the lamps, the photoconductive cells 80 and 81 and thus control the output of the power module to control the direction and torque of the correction roll. By this method I can utilize electronically-generated external signals such as are produced in photoelectric means and squared up in bistable multivibrators connected to terminal pairs 82' and 83 in FIG. 6 to control the circuit in FIG. 3. By using an optical system in conjunction with the modification shown in FIG. 6, it is possible to render my invention automatic in a manner somewhat like the systems revealed, for example, in Patents 2,233,644, 2,311,674, and 3,077,656.

Table of circuit components Rectifiers 50, 57, 62, 69 2Nl773A. Diodes 51, 55, 63, 67 1N537. Capacitors 52, 56,- 64, 68 m. Resistors 54, 75, 66, 76 1009. Potentiometers 27, 27' 60009 ganged potentiometers. Diodes 58, 59, 60, 61, 70, 71,

72, 73 1N1342. Motor M Inland torque motor, panc a k e-permanent-magnet type. Cells 80, 81 Clairex photocell, s e ri e s 800. Lamps 78, 79 NE2 neon lamp or Kay I Electric type 15 or type 30-Pinlites.

I do not limit my invention to the exact forms shown in the drawingsfor changes may be made therein within the scope of the following claims.

I claim:

1. Apparatus for receiving a Web of material and straightening the web in the transverse direction of the material by selectively advancing or retarding adjacent portions of the material in the longitudinal direction, comprising:

(a) composite power-driven roller means divided into plural rolls rotatably supported in side by side relationship on a common fixed shaft, and the composite roller means extending at least the full width of the web;

(b) idler roller means disposed parallel with the driven roller means and each idler means being divided into plural adjacent idler rolls journaled mutually adjacent about a common axis, each idler roll being coextensive with and in alignment with a driven roll;

(c) direct-current torque motor means housed within each driven roll and fixed on said common shaft and having commutator and brush means connected with electrical input wiring extending out of said driven roller means through the shaft;

(d) separate direct-current power supply means coupled to each input wiring and each controllable to selectively deliver power of reversible polarity and adjustable magnitude to the corresponding motor means;

(e) rheostat means connected to each power supply means and adjustable to selectively control the magnitude and :polarity of the power supplied to the corresponding torque motor; and

(f) a cluster of control lever means respectively coupled to said rheostat means and each having a centered neutral position in which no power is furnished to the torque motor.

2. Apparatus for receiving a web of material and straightening the web in the transverse direction of the material by selectively advancing or retarding adjacent portions of the material in the longitudinal direction, comprising:

(a) composite power-driven roller means divided into plural rolls rotatably supported in side by side relationship on a common shaft and the roller means extending at least the full width of the web;

(b) idler roller means disposed parallel with the driven roller means and each idler means being divided into plural adjacent idler rolls journaled mutually adjacent about a common axis, each idler roll being coextensive with and in alignment with a driven roll;

(c) torque motor means housed within each driven roll and fixed on said common shaft and having electrical input wiring extending out of said driven roiler means through the shaft;

(d) separate power supply means coupled to each input wiring and each controllable to selectively deliver power to the corresponding motor means; and

(e) power supply control means connected with each power supply means to selectively control the magnitude and direction of the torque applied to the web by the driven roll in that position.

3. Apparatus for receiving and advancing a web of woven material and for straightening the web in the weft direction of the material by selectively advancing or retarding adjacent longitudinal portions of the material in its warp direction, comprising:

(a) composite power-driven roller means divided into plural rolls rotatably supported in side by side relationship on a hollow fixed shaft and the roller means extending at least the full width of the web;

(b) two sets of idler roller means each disposed parallel with the driven roller means and therebelow for pulling the material tight around at least half the periphery of the driven roller means and each idler means being divided into plural adjacent idler rolls journaled mutually adjacent about common axes, each idler roll being transversely coextensive with and in alignment with a driven roll;

() direct-current torque motor means housed within each driven roll and fixed on said shaft and having commutator and brush means connected with electrical input wiring extending out of said driven roller means through the shaft;

(d) separate direct-current power supply means coupled to each input wiring and each controllable to selectively deliver power of reversible polarity and adjustable magnitude to the corresponding motor means;

(e) rheostat means connected with each power supply means and adjustable to selectively control the magnitude and polarity of the power supplied to the corresponding torque motor;

(f) an instrument and control panel having a control position corresponding with each of said power supply means, and having a control lever in each of said positions and coupled through motion-increasing gearing with the corresponding rheostat means; and

g) a meter opposite each control lever and indicating the direction and magnitude of the power supplied by the associated power supply means.

4. ln apparatus for straightening the weft of a woven material and said apparatus having a composite roller divided into plural side-by-side rotatabie rolls supported on a common shaft, and having means for holding the material in snug engagement with said rolls and having a source of power, the improvement comprising:

(a) plural reversible torque motor means supported on said shaft and each motor means being coupled to apply torque to one of said rolls either with or against the direction of movement of said material through the apparatus; and

(b) plural control means each connected between said source and a different reversible motor means and operative to deliver power to the motor means to control both the instantaneous magnitude and direction of its torque separately from the torque of any other of the motor means.

5. In apparatus as set forth in claim 4, each motor means comprising a stator fixed to said shaft and a rotor attached to a roll and housed therewithin.

6. In apparatus as set forth in claim 5, said control means comprising a cluster of control levers arranged side-by-side in the same sequence as the rolls whose torque they control, and each lever having a neutral position in the center of its travel with forward and reverse torque positions on either side thereof.

7. In apparatus as set forth in claim 4, each motor means comprising a DC. motor including a stator fixed to said shaft and a rotor attached to a roller and commutator means operatively connected between said stator and rotor; and said control means each comprising means for reversing the polarity of the power supplied to the motor means and for controlling its magnitude.

3. In apparatus as set forth in claim 4, said control means comprising a cluster of power control levers each operatively connected to control one motor means, the levers being arranged in side-by-side immediately adjacent relationship in the same sequence as the motor means which they control whereby when the levers are moved so that a line through their positions resembles the instantaneous contour of the weft approaching the rolls, the apparatus will tend to straighten the weft.

9. In apparatus as set forth in claim 8, meter means adjacent to each control means and connected thereto to indicate the instantaneous magnitude and direction of the torque applied to the associated roll.

References Cited by the Examiner UNITED STATES PATENTS Re. 9,452 11/1880 Palmer 26-51.3 1,272,924 7/1918 Doran 2651.3 1,690,334 11/1928 Durrant 26-513 1,725,740 8/ 1929 Schulte 198127 1,868,825 7/1932 Grosjean 198-127 2,355,557 8/1944 Radley et al 318-262 2,669,685 2/ 1954 Lichtenfels 318262 3,156,964 11/1964 Leimer et a1. 26--51.3

FOREIGN PATENTS 161,023 6/ 1905 Germany. 972,934 11/1959 Germany. 1,131,635 6/1962 Germany.

DONALD W. PARKER, Primary Examiner.

R. R. MACKEY, Examiner. 

4. IN APPARATUS FOR STRAIGHTENING THE WEFT OF A WOVEN MATERIAL AND SAID APPARATUS HAVING A COMPOSITE ROLLER DIVIDED INTO PLURAL SIDE-BY-SIDE ROTATABLE ROLLS SUPPORTED ON A COMMON SHAFT, AND HAVING MEANS FOR HOLDING THE MATERIAL IN SNUG ENGAGEMENT WITH SAID ROLLS AND HAVING A SOURCE OF POWER, THE IMPROVEMENT COMPRISING: (A) PLURAL REVERSIBLE TORQUE MOTOR MEANS SUPPORTED ON SAID SHAFT AND EACH MOTOR MEANS BEING COUPLED TO APPLY TORQUE TO ONE OF SAID ROLLS EITHER WITH OR AGAINST THE DIRECTION OF MOVEMENT OF SAID MATERIAL THROUGH THE APPARATUS; AND (B) PLURAL CONTROL MEANS EACH CONNECTED BETWEEN SAID SOURCE AND A DIFFERENT REVERSIBLE MOTOR MEANS AND OPERATIVE TO DELIVER POWER TO THE MOTOR MEANS TO CONTROL BOTH THE INSTANTANEOUS MAGNITUDE AND DIRECTION OF ITS TORQUE SEPARATELY FROM THE TORQUE OF ANY OTHER OF THE MOTOR MEANS. 